Question

Enthalpy of air is 15 J and enthalpy of water vapor is 20 J, if the total enthalpy of the system is 25 J, what is the humidity of the system?

(a) 10%

(b) 50%

(c) 100%

(d) 200%

The question was asked in an international level competition.

I'd like to ask this question from Degrees of Freedom Analysis in Steady-State Process topic in chapter Humidity Charts & their Use, Analysis of the Degrees of Freedom in a Steady – State Process, Solving Material and Energy Balances Using Process and Unsteady State Material and Energy Balances of Basic Chemical Engineering

Answer 1

Right answer is (b) 50%

Best explanation: 25 = 15 + 20*H, => H = 0.5, => H = 50%.